1. Field of the Invention
The present invention relates, generally, to windshield-wiper assemblies and, more specifically, to a beam-blade windshield-wiper assembly having an elongated backbone that is supported in cantilevered fashion.
2. Description of the Related Art
Conventional windshield-wiper assemblies known in the related art include some type of blade assembly mounted to a wiper arm that, in turn, is mounted adjacent a vehicular windshield and pivotally driven to impart reciprocating motion to the blade assembly across the windshield. A rubber wiper-element is supported by the blade assembly and contacts the windshield across the surface to be wiped. The wiper element often incorporates one or more metal strips that act to reinforce the wiper element and facilitate wiping contact by the wiper element across what is typically a glass surface.
One type of blade assembly commonly known in the related art employs a xe2x80x9ctournamentxe2x80x9d style superstructure having a primary lever carried by the wiper arm, two secondary levers, and as many as four or more tertiary levers. Each secondary lever is articulated to the primary lever at a pivot point located at an opposed, lateral end of the primary lever. Similarly, each tertiary lever is articulated to a secondary lever at a pivot point located at an opposed, lateral end of its associated secondary lever. xe2x80x9cTournamentxe2x80x9d style blade assemblies often utilize steel vertebra that are mounted relative to the wiper element to provide a force distribution of the wiper element against the glass.
The blade assembly is located on an end of the wiper arm and represents a significant portion of the inertia generated by the windshield-wiper assembly in operation. Furthermore, the profile of the blade assembly as it reciprocates across the windshield is an important design consideration as it relates to avoiding wind-lift at higher vehicle speeds. In addition, since components of the windshield-wiper assembly are often visible, even when the windshield-wiper assembly is not in operation, the appearance of the components is also an important design consideration.
Beam-style blade assemblies are also known in the art. The beam-blade assembly includes a single, elongated, homogenous strip forming a backbone. The backbone has a formation at a central position of the backbone for connection to the pivotally driven wiper arm, which applies a downward force and moves the beam-blade assembly across the windshield. The backbone is usually curved along the same plane of curvature as that defined by the windshield. The wiper element is secured to the backbone. Examples of beam-blade assemblies can be found in U.S. Pat. Nos. 5,325,564 and 5,485,650 issued Jul. 5, 1994 and Jan. 23, 1996, respectively, both in the name of Swanepoel.
The backbone disclosed in the Swanepoel ""564 and ""650 patents is made from spring steel and preferably tapers in width from the center toward the free ends, or, tips, of the backbone. Swanepoel teaches that the thickness, width, and radius of curvature of the backbone should preferably be matched along the length of the backbone such that the backbone will provide a force-per-unit-length distribution that increases toward both tips of the backbone when the windshield-wiper assembly is in use. The backbone is pressed downwardly intermediate its tips onto the surface of the windshield. Beam-blade assemblies exhibit the advantages of having a lower profile, consisting of fewer parts, and being more pleasing in appearance as compared with xe2x80x9ctournamentxe2x80x9d style blade assemblies.
While beam-blade assemblies have been proposed for use with windshields, they have not been proposed or generally adopted for use with rear vehicle windows. The wiper assemblies employed on rear windows are substantially of the tournament style. However, these assemblies result in a relatively long wiper arm and a profile that partially includes most of the wiper arm, approximately half of the backbone, and the space between them. Such assemblies commonly employed in the related art are not optimally thin and, thus, not optimally aesthetically pleasing.
Accordingly, there continues to be a need in the art for beam-blade windshield-wiper assemblies having a lower profile, simpler parts, and a more pleasing appearance.
The present invention overcomes the disadvantages in the related art by providing a cantilevered beam-blade windshield-wiper assembly. The assembly includes a longitudinally extending backbone having first and second ends. A wiper element is mounted to and extends a substantial portion of the longitudinal extent of the backbone and is adapted for wiping engagement with a windshield. A wiper arm is connected to the first end of the backbone such that the backbone is supported in cantilevered fashion by the wiper arm at the first end and the second end is disposed distal the wiper arm. The wiper arm is adapted to be reciprocally driven with respect to the windshield, apply a biasing downward pressure to the backbone in the direction of the windshield, and move the backbone reciprocally across the windshield.
One advantage of the cantilevered beam-blade windshield-wiper assembly of the present invention is that it is more compact and has a lower profile when compared to conventional tournament-style windshield-wiper assemblies known in the related art. More specifically, the beam-blade windshield-wiper assembly of the present invention provides a backbone connected at an end thereof to a wiper arm and extending away from the wiper arm. As a result, no substantial portion of the backbone shares a plane co-extensive with the wiper arm and perpendicular to the windshield. Still, the backbone is fully operative to reciprocate across a windshield in conjunction with a wiper element to wipe the surface of the windshield.
Another advantage of the cantilevered beam-blade windshield-wiper assembly of the present invention is that it has simpler parts while providing improved performance when compared to conventional tournament-style windshield-wiper assemblies known in the related art.
Another advantage of the cantilevered beam-blade windshield-wiper assembly of the present invention is that it is more pleasing in appearance when compared to conventional tournament-style windshield-wiper assemblies known in the related art.
Another advantage of the cantilevered beam-blade windshield-wiper assembly of the present invention is that because it has generally fewer parts, it costs less to manufacture when compared to conventional tournament-style windshield-wiper assemblies known in the related art.